text:
Max Range Relationship to Altitude for Propeller-Driven Aircraft

Chapter 11 of the PHAK states, "If a change in altitude causes identical changes in speed and power required, the proportion of speed to power required would be unchanged. The fact implies that the specific range of a propeller driver aircraft would be unaffected by altitude. Actually, this is true to the extent that specific fuel consumption and propeller efficiency are the principal factors that could cause a variation of specific range with altitude. If compressibility effects are negligible, any variation of specific range with altitude is strictly a function of engine/propeller performance. An aircraft equipped with a reciprocating engine experiences very little, if any, variation of specific range up to its absolute altitude."
I looked at the POH's of both a Cessna 172 S model, and a Piper Warrior, and it seems as though both airplanes experience a significant increase in range with higher cruising altitudes. Can anyone explain this?

Related: https://aviation.stackexchange.com/questions/60762/does-altitude-influence-the-flight-range-of-an-engine-driven-aircraft? , https://aviation.stackexchange.com/questions/4967/how-can-you-find-the-best-altitude-for-range-or-speed? .  See other questions in "related" sidebar also.

Note that the graph you posted and the relevant text are perfectly correct as long as you consider the speed as being TAS. Might it be that the Cessna and Piper charts consider IAS instead?

Wouldn't it be nice if they listed IAS in the range charts.  IAS/TAS calculators are available on line.

@RobertDiGiovanni Yes, having both would be very nice! All told, true airspeed is probably more helpful for cross country planning, but it would be nice to know what you should expect to see on the airspeed indicator in cruise!

A change in altitude doesn't cause identical changes in speed and power required. Assuming that the drag is dominated by parasitic drag (typically true at cruise speed), the drag force is proportional to the equivalent airspeed squared, and power required is drag force times true airspeed:
$$\text{Power required}\propto (\text{EAS})^2\times\text{TAS}$$
Equivalent airspeed is given by:
$$\text{EAS}^2=\frac{\text{density}}{\text{sea level density}}\text{TAS}^2$$
So power required is related to true airspeed by:
$$ \text{Power required}\propto\text{density}\times(\text{TAS})^3$$
This means that, assuming fixed power, true airspeed, and thus specific range, is inversely proportional to the third root of the air density:
$$ \text{Specific range}\propto\text{True airspeed} \propto \sqrt[3]{\frac{1}{\text{density}}} $$
As an example, the density at 8000 feet density altitude is 78.6% of that at sea level. This gives a specific range about 8% higher than at sea level for the same power.
This relation falls apart at high altitudes- as you get to a higher and higher altitude you need to pitch up you reach the minimum drag airspeed. If you keep going higher with the same power, the drag increases, the specific range decreases, and pretty quickly you end up near stall speed.
Note also that ranges in the POH's you're reading also include the fuel required to climb up to that altitude in the first place.
Here is the specific range of a Cessna 152, based on POH cruise data and plotted versus equivalent airspeed:

The blue curve is a fit to the data based on the model outlined above.

"Assuming fixed power" implies a change in altitude does not affect IAS.  More correctly, it's fixed thrust.  As long as required thrust, therefor IAS, can be maintained, increased TAS results in greater range, literally miles per gallon.

@RobertDiGiovanni No, I'm not assuming fixed thrust. I'm assuming fixed power, the same amount of fuel going in. Maintaining the same thrust at higher density altitudes requires more fuel/power and this complicates the analysis. With fixed power, IAS goes down with altitude. IAS goes down slowly enough that TAS goes up. But eventually IAS gets low enough that the induced drag starts to get significant and the IAS plummets and TAS decreases.

@RobertDiGiovanni The engine also loses maximum power with altitude and at some point is unable to maintain a given power. But this is a separate effect. Even with a fixed power, specific range decreases past a certain altitude where induced drag becomes too significant.

I think we can agree there are many ways of looking at it.  Interestingly, if you have fixed power (same amount of fuel going in) you have to open the throttle flap more at altitude to get fixed air (to match fixed fuel).  Looking at the range graph in the POH, one might wonder exactly what "fixed power" is at altitude?  Are they leaning the mixture?

@RobertDiGiovanni Yes, they are leaning the mixture. For instance, look at a C152 POH. Every point is form "recommended lean" mixture, and the true airspeed, if plotted versus density for, say, 75% power gives that $(\text{density})^{-\frac{1}{3}}$ relation I mentioned.

@RobertDiGiovanni Higher RPM doesn't necessarily mean that the engine is working harder. Higher power does. The same power at higher altitudes gives higher RPM- because the air is thinner it takes the engine less effort to spin the same speed. The RPM for fixed power follows basically the same $\text{RPM}^3\times\text{density}=\text{constant}$ relation.

@RobertDiGiovanni Anyway, since what we're interested in is specific range, to compare apples to apples you need to look at the same fuel intake (i.e. power) at two different altitudes.

@RobertDiGiovanni 12000 is the service ceiling. Apparently Cessna thinks nobody is crazy enough to want to take a 152 any higher than that. ;)

@Chris, the units of EAS^2 = rho/rho * TAS do not match, should it be  EAS = rho/rho * TAS. If so then the density in the power required should be density^2

@ROIMaison Yep, that's a typo. Thanks! And no, it's EAS^2=rho/rho * TAS^2- I think the rest of the math is right, I just missed the ^2.

Best specific range is at Vy.  Yes indeed!  +1 Good work.


text:
The recording of takeoffs and landings in a logbook, particularly in the context of multipilot operations?
It has recently occurred to me that I may not be correctly documenting my takeoff and landings in my logbook. I am currently using a paper logbook (until I unfreeze my ATPL) and have been creating a duplicate spreadsheet as a backup.
However, I have recently decided to switch to a popular logbook app instead of using the spreadsheet. I set up the app with the default settings, indicating my role as a First Officer in an airline. As a pilot of Boeing 737s, I have been recording all the landings I make, whether I am the pilot flying or the pilot monitoring. My rationale is that these TOs/LDGs should be recorded within my total TOs/LDGs, as the responsibility for takeoffs and landings lies with both crew members. However, I have noticed that the logbook app only registers the takeoff or landings when I am the Pilot Flying.
I am curious to know if there are any specific EASA regulations regarding the documentation of takeoffs and landings.

Logging a landing when you are not sole manipulator of the controls seems highly unethical at best.

@Michael Hall Hmm not sure if I would agree. The 737 is not designed to be flown single pilot ops. My presence in the flight deck and distinct SOPs for pilot monitoring make me an indispensable contributor to that approach/landing (and takeoff for that matter).

For example. As pilot monitoring, I call if the approach is stable or unstable at the landing gate. I manipulate the flaps, I lower the gear, I put the engine start switches in continuous, I put the engine anti ice on, I do a RECALL, I run the landing checklist….

I don't disagree that you are a valuable and required member of the crew, only that "monitoring" is not  flying.  By definition.  It wouldn't even cross my mind to log a landing when monitoring.

Have you asked your Chief pilot or other crews how they do it?  Does your company SOP address it?

@MichaelHall, you might get a kick out of this. For the boat, a copilot/NFO can log arrested landings as type Y (day) or Z (night). I don’t know of any pilot that did it, but it was possible.

Our NFO's did it.  For the patch.  Caused plenty of eyerolls amongst the single seat guys.  (and, quietly, the single anchor guys in our own squadron...)

Is there any requirement to have PM'd a landing or a number of landings, in the past XX days?  Can one be current to land as PF but not as PM?  While I fly in FAA-land and not EASA-land, any count of landings as PM is entirely in the "useless trivia" category, and isn't tracked by our airline nor anybody else I've ever heard of. Maybe EASA differs. The paper copy is your book, track anything you want to, but claiming (intentionally or not) a PM'd landing as if you were the PF can get people in major trouble in most places.

@RalphJ, Well said!  If you were to edit that into an answer I would upvote it.

@MichaelHall Thanks, but EASA can have enough differences from FAA that extrapolating from the one to the other doesn't really make for a great answer.  Especially given what we now have below, quoting EASA regs as definitively "landing" = "PF landing."

I didn't see bus driver's newest answer.  That sticks a fork in the issue, even if it is a bit too brief in my opinion.

See EU FCL.050.
“column 8: indicate the number of landings performed as pilot flying by day or night;”
https://www.easa.europa.eu/sites/default/files/dfu/Part-FCL.pdf#page39

Your logbook must contain enough information to determine whether you meet the relevant recency requirements of your certificate.
The wording of this is not super clear in EASA regulations. From FCL.060:

A pilot shall not operate an aircraft
in commercial air transport or carrying passengers [...] as PIC or co-pilot unless he/she has carried out, in the preceding 90 days, at least 3 take-
offs, approaches and landings in an aircraft of the same type or class or an FFS representing
that type or class. The 3 take-offs and landings shall be performed in either multi-pilot or
single-pilot operations, depending on the privileges held by the pilot.

Which leaves open the question of what counts as "carrying out" a takeoff, approach, and landing. From the night recency requirements in the following paragraph (emphasis mine):

[A pilot shall not operate] as PIC at night unless he/she [...] has carried out in the preceding 90 days at least 1 take-off, approach and landing
at night as a pilot flying in an aircraft of the same type or class or an FFS
representing that type or class

Night recency specifies "pilot flying." By implication "carrying out" does not imply that you are the pilot flying, and so the pilot monitoring can log the takeoffs, approaches, and landings towards their recency requirements.
Note that this is a deviation from ICAO. The relevant ICAO documentation is crystal clear that you must be the pilot flying for it to count. From Annex 6, Part I, Section 9.4.1.1:

The operator shall not assign a pilot-in-command or a co-pilot to operate at the flight controls of a type or
variant of a type of aeroplane during take-off and landing unless that pilot has operated the flight controls during at least three
take-offs and landings within the preceding 90 days on the same type of aeroplane or in a flight simulator approved for the
purpose.

It would be a good idea to log PF and PM landings separately, since if you fly outside of EASA airspace you may be beholden to the more restrictive currency requirements of the relevant country. You need to distinguish between PF and PM for night recency anyway.

I'm with 757toga on this. Sometimes it is safe to infer that something is permitted by omission of a specific qualifying statement, but here, (especially if you throw in CFR 61.57) there are multiple references to establish the intent that the pilot flying is the only one performing the landing, and therefore should be the only one to log it. Obviously the App developers also see it that way.

Excellent answer, I just disagree with the interpretation: "By implication "carrying out" does not imply that you are the pilot flying, and so the pilot monitoring can log the takeoffs, approaches, and landings towards their recency requirements."  Odd perhaps, because I generally favor the most advantageous and liberal interpretation.  I guess it stems from my personal aversion to taking credit, (or blame) for any landing when someone else had the controls.

@757toga Interestingly, the EASA regulations require this recency to "operate" the aircraft, whether as PF or PM, whereas ICAO/FAA only requires recency to manipulate the flight controls/act as PIC. This is, in my opinion, another point in favor of the idea that PM duties count for recency, since you require the recency even to act as PM. It makes some sense- if you're going to act as PM on landing, what better way to stay proficient is there than acting as PM on some landings?

But in any case I agree it's not 100% clear, and any pilot would be wise to confer with their local authorities before relying on any legal interpretations they read on the internet. ;)

@MichaelHall I would be curious to see any EASA references that establish the intent that the PF is the one performing the landing. Obviously that is the case in the US and most other ICAO countries, but it would hardly be the first case where EASA has dramatically different rules from many other authorities.

@757toga It is important not to confuse recency/currency with proficiency. Do you feel that someone who acts as PF for only one landing a month is likely to remain proficient?

@757toga I agree, it's a very minimal standard. I would hope that most airline pilots have many more than 3 takeoffs and landings in 3 months! Preferably both as PF and as PM.

"I would be curious to see any EASA references that establish the intent that the PF is the one performing the landing."  Well, the reference you provided on night landings states "pilot flying" clearly.  You even bolded it.  It is the omission of this same phrase in the first quote that leads you to infer that during the day time both pilots are considered to have performed the landing.

@MichaelHall By that logic, FAA day currency requires three landings to a full stop. ;)

Touche!  Well played my friend.  I disagree of course, but don't have a snappy comeback ready...

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

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text:
Frontier Flight 1929 3/21/24 DIVERTED - HELP FIND ATC RECORDING
My family was on frontier flight 1929 on 3/21/24 from PWM. It was diverted back to PWM within minutes of take off. I am trying to find the ATC recording for the reason why it was diverted. Can anyone help get this clip? been trying to find it on liveatc.net with no luck!

I'm curious what announcements were made to the passengers, both in flight and after landing. It's tough for the crew because besides being busy with the procedure, they have to try not to alarm the 99% of passengers who know nothing about airplanes other than what they watch on Mayday!  and will likely freak out if they hear there is engine trouble. From your question it sounds like no reason was given for returning, but surely they said something? Was it a vague "we need to go back and check something" type of announcement?

It's on liveatc's PWM "tower 2" feed, here's the specific file. It took off and they were handed off to departure.
Going over to that frequency, they check in at 1500 feet and are cleared to 10k feet. They then call back in and say "we're gonna need to come back into Portland for a landing". They stated they were having surging on one of their engines. They said "no equipment necessary", so they weren't concerned at all.
Departure asked for their numbers, which implies that they may have called an emergency for the airplane. They listed passenger counts and fuel quantity, which is standard.
The plane then came back in and tower asked if they needed anything. They said "everything worked out".
Pretty standard stuff.
The plane, N334FR, hasn't been used since- though that was Thursday, today's Sunday, so maintenance may not even be looking at it yet.

For the record, the involved plane (N334FR) completed its first flight today, 9 days after the diverted flight.

The relevant part of the ATC recording is available here, at around a time stamp of 11:20. They were having some surging in one of the engines.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Can you identify this plane? Picture from ca1942, maybe Taylorcraft
This was my grandfather's plane, picture taken, I believe, in 1942.  My grandparents are long gone and I have no one to confirm the ID of this plane, but from internet searches, it looks like a Taylorcraft BC-65.  Would the experts out there please weigh in?
Possible Taylorcraft BC-65

Yes, that is a Taylorcraft BC-65, or possibly a BL-65.  The configuration of the wing struts and the struts visible inside the windscreen are all consistent with B-series Taylorcraft.  The greater depth of the windscreen and side windows helps distinguish it from later variants such as the BC12-65. The small trim surface visible below the horizontal tail is further clue that this is a BC-65 or BL-65.  Here are some links to photos of other BC-65s or BL-65s with the same trim surface:
http://russellw.com/photoalbum/photo_query_results.asp?qModel=eBL-65 (scroll down to 4th photo)
https://www.aircraft.com/aircraft/201009513/n23683-1939-taylorcraft-bl-65
https://www.airliners.net/photo/Untitled/Taylorcraft-BC-65/623696
https://www.airliners.net/photo/Untitled/Taylorcraft-BC-65/5214477
https://commons.wikimedia.org/wiki/File:Taylorcraft_BC-65_%28N24393%29.jpg
https://www.skytamer.com/Taylorcraft_B.html

Now, if someone finds a photo of a BC12-65 with that same trim surface, I'll have to modify this answer-- (I couldn't find one)-- but even in that case I still believe it is the older BC-65 or BL-65.


text:
Confusion about the 6 month timeline for instrument currency
14 CFR 61.57 (c)(1) says that "within the 6 months PRECEDING the month of flight, that person has performed the following tasks..." (6 instrument approaches and the rest). To keep things simple, let's imagine that I take an instrument checkride or an IPC on December 31st. I don't fly for a few months, and then I shoot 5 instrument approaches and perform a hold in June. On July 1st, I shoot an instrument approach (with a safety pilot as I am no longer current). Am I now able to act as PIC for an IFR flight on July 2nd? Because in the six calender months preceding the month of the flight (January-June, the six moths preceding July) I don't have 6 instrument approaches. Even my instructor was a bit perplexed, and he couldn't give me a clear answer.
Thank you

Seems odd that you'd be ineligible for the rest of July, but it seems you'd definitely become eligible on August 1. Curious to see how this gets answered.

Short answer:  Once you have completed the instrument approach with a safety pilot on July 1, you would be instrument current for six calendar months from June.  Therefore you are considered instrument until December 31 of that year, as, within the past six calendar months, you have accomplished at least six instrument approaches, holding patterns, and navigation by electronic instruments per §61.57.
That currency simply applies to any time period, within six calendar months from a proposed flight, that you have meet the requirements of §61.57.
Some additional examples: suppose you complete another two instrument approaches in July, one in September, flying the published missed and hold, and then two approaches in October, you would be instrument current all the way until January 31.

It depends on how you interpret "within." I think in context "within the 6 calendar months preceding the month of the flight" can reasonably be construed to mean "more recently than six calendar months before the flight."
It doesn't make any sense that in the situation you've described you could perform as many approaches and the like as you like in July and not be able to restore your currency until August. When one interpretation of a word leads to a nonsensical law it is reasonable to interpret it another way.


text:
Logging Instrument approach if if entering IMC past the FAF, but in VMC before and passing the FAF
Can an Instrument rated pilot log an instrument approach if  entered IMC past the FAF to minimums but was VMC prior and just past the FAF? What is your source?

Yes, IAPs are designed to bring aircraft down through IMC conditions to the airport environment to make a landing. If IMC conditions are encountered at any point between FAF and DA/MDA, the approach can be logged. FAA InFO 15012 provides guidance on what requirements have to be met in order to log an IAP.
Example 1 on page 3 is the most similar to the question you are asking:

Example 1: An instrument-rated pilot, conducting a flight under an IFR clearance, approaches the destination airport, aligned with runway 33 and 17 miles out. ATC issues a clearance that states, “. . . cleared ILS runway (RWY) 33R approach as published, maintain 3000, advise when established.” The pilot operates the aircraft solely by reference to instruments, complies with the clearance, and continues in IMC—while remaining established as published on each required IAP segment. The aircraft descends past the final approach fix (FAF) as the pilot contacts the control tower and the aircraft transitions from IMC to visual metrological conditions (VMC) before reaching the DA. At this point, the pilot receives an ATC clearance to land; the pilot visually confirms runway environment assured and lands. In this example, the IAP complies with § 61.51(g)(3) and § 61.57(c); therefore, the pilot may log this IAP.

FAA InFO 15012 says that the approach must be done under actual or simulated instrument conditions, or a combination thereof, with the aircraft being operated solely by reference to instruments, for every required approach segment. It allows for approaches to be counted if the approach is conducted in IMC and the pilot breaks out beyond the final approach fix, but it does not give a similar exception for any other part of the approach.
So it seems that the answer is no- you would need to be wearing a hood from the point you initiate the approach all the way to when you first enter IMC. Once you are in actual IMC you can take the hood off, and then once you break out you can land and log the approach.


text:
McCauley propeller models IC235/LFA7570 and IA170E/JHA7660
I am writing to inquire about the pitch specifications for the following McCauley propeller models:

IC235/LFA7570 with a maximum diameter of 75 inches and minimum diameter of 74 inches.
IA170E/JHA7660 with a maximum diameter of 76 inches and minimum diameter of 75 inches.

Both models have 2 blades. I would appreciate it if you could provide me with the detailed pitch information for these propellers.
Thank you for your help.

The suffix numbers are the propeller diameter followed by the geometric pitch at the .75 radius station. So they are 70 inches of pitch and 60 inches of pitch, respectively, at a point 75% of the radius from the center of the blade (28.1 inches and 28.5 inches, respectively).
The pitch in inches is how far forward a propeller of that pitch would go forward in one revolution if you imagine air were a rigid substance. It is related to the actual blade angle at the .75 radius station by the following formula:
$$\text{pitch}=\frac{3\pi}{4}\text{diameter}\times\tan\left(\text{blade angle}\right)$$
Using this formula, the blade angles are about 21.6° and 18.5° respectively.

Ah! LFA7570 means LFA = something; 75 = inches in diameter, and 70 = inches of pitch at 75% of radius (52.5 inches). What does "70 inches of pitch" mean? I'd expect pitch to be in degrees. (Yes, it took me some head scratching to figure out how to interpret your text description...)

@FreeMan Imagine air as a rigid substance, and the propeller as a screw screwing through the air. The geometric pitch in inches is how far forward a propeller of that pitch would go through the air in one revolution.

Ah, got it. Thanks, that makes sense now.


text:
Can I log PIC time without a valid medical?
Here is the scenario. Could you please tell me if
this pilot can log PIC time?
I am a private pilot and my medical is expired.
I want to fly so I am trying to fly with another private pilot friend.
My friend has a valid medical and flight review.
The flight will be VFR, in VFR conditions.
I am going to fly so I will be the sole manipulator. Can I do so without a medical? Can my friend be acting PIC, with just me flying and logging PIC?
My friend is going to watch me.

What is preventing you from going an getting a medical or going through the BasicMed process?

@SMSvonderTann Seems like rather private information to me.

Also irrelevant to the question, since the reasons have nothing to do with improving the questions or how we would frame an answer.

No. You need to dig into the regulations a bit to get at the answer:
§ 61.51(e):

Logging pilot-in-command flight time.

(1) A sport, recreational, private, commercial, or airline transport pilot may log pilot in command flight time for flights-

(i) Except when logging flight time under § 61.159(c), when the pilot is the sole manipulator of the controls of an aircraft for which the pilot is rated, or has sport pilot privileges for that category and class of aircraft, if the aircraft class rating is appropriate;

This seems to imply you can at first glance, but you need to dig into the definitions of the terms used. § 1.1 defines "flight time":

Pilot time that commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing

and then § 61.1 defines "pilot time":

Pilot time means that time in which a person -
(i) Serves as a required pilot flight crewmember;
(ii) Receives training from an authorized instructor in an aircraft, full flight simulator, flight training device, or aviation training device;
(iii) Gives training as an authorized instructor in an aircraft, full flight simulator, flight training device, or aviation training device; or
(iv) Serves as second in command in operations conducted in accordance with § 135.99(c) of this chapter when a second pilot is not required under the type certification of the aircraft or the regulations under which the flight is being conducted, provided the requirements in § 61.159(c) are satisfied.

The only one here that could possibly apply to you, assuming your friend is not a CFI, is the first. However, you cannot serve as a required flight crewmember without a medical, as stated in § 61.3(c)(1):

A person may serve as a required pilot flight crewmember of an aircraft only if that person holds the appropriate medical certificate issued under part 67 of this chapter, or other documentation acceptable to the FAA, that is in that person's physical possession or readily accessible in the aircraft. Paragraph (c)(2) of this section provides certain exceptions to the requirement to hold a medical certificate.

unless one of the exceptions in § 61.3(c)(2) applies to you.
In short, you can only log "flight time," which is a type of "pilot time," which only accrues if you are a "required flight crewmember." Since you are not allowed to be a required flight crewmember without a medical, you can't log time either.
You can log PIC time if you are receiving training from a CFI in a plane you are rated for. If your medical has lapsed and you don't have a medical condition that makes flying unsafe, picking up some training from a CFI is a safe and legal way to continue flying and logging time while you work on getting your medical in order.

Um... there are plenty of times that rated pilots swap controls, operate as "sole manipulator", yet are not both required crewmembers.  Does that time not count?

@MichaelHall Good question. I feel like it should, but I can't find a strong citation that it is the case. I suppose one could argue that the pilot flying (at any given moment) is the only required crewmember? Which would mean whoever is flying could log, but the pilot not flying cannot.

From the Grau interpretation, "For purposes of this provision, a required pilot flight crewmember means a pilot assigned to
perform a duty in an aircraft during flight time." Perhaps they both count as required crewmembers? The PNF still can't log PIC time in that case since 61.51(e)(1)(iii) specifies that the additional pilot must be required by regulation or type certification.

It is an interesting interpretation.  I can see your logic.

I would stop at 61.51(e) and answer yes.  If you try hard enough you can talk yourself out of almost anything.

@MichaelHall Indeed, under the definition of a required crewmember meaning "a pilot assigned to perform a duty in an aircraft during flight time," swapping controls (i.e. assigning a pilot to perform the duty of flying the airplane) would indeed change who is a required crewmember and so who could log. I think it makes sense to draw a distinction between assigning a rated, current, and legal pilot to fly versus allowing a passenger (whether a pilot or not) to manipulate the controls under supervision. Even if a passenger is a pilot, if they aren't current or otherwise legal [...]

[continued] I don't think assigning them the duty of flying is in any way legal.

"Even if a passenger is a pilot, if they aren't current or otherwise legal I don't think assigning them the duty of flying is in any way legal."  The CFRs make no mention of "assigning them the duty of flying".  They distinguish between acting as PIC and sole manipulator.  I agree that someone acting as PIC cannot assign acting PIC duty to someone not medically current.  But they can let a rated pilot, (even a non pilot!) manipulate the controls.

And the regs clearly say that you can log it in "an aircraft for which the pilot is rated" without imposing an additional restriction that the medical certificate be current.

@MichaelHall As I said in my comment on your post, I don't think you can interpret 14 CFR § 61.51(e) without the definition of the term "flight time," which clearly requires a pilot to be a "required pilot flight crewmember" (i.e. be assigned a duty, according to the Grau interpretation. In any case one is not a "flight crewmember," required or otherwise, unless assigned a duty), or to be receiving/giving training, or to be serving as SIC under certain part 135 operations. The pilot needing to be rated is an additional requirement over the time counting as "flight time" in the first place.

Where did you find that definition of "pilot time"?  I don't see it alphabetically in 1.1.

@MichaelHall It's in 61.1.

While I can follow how you arrived at your conclusion, I think we need to agree to disagree on this one.  Thorough knowledge of the FARs is expected of pilots, but there is also a reasonable expectation that in any regulation the key points be included within the applicable section.  As I mentioned somewhat flippantly before, I could probably dig deep enough to find a way to disallow any number things by omission or linking to a requirement listed in some different section and context.  Anyway, time for me to move on with my weekend...

@MichaelHall Certainly reasonable people can disagree on regulation! Otherwise we wouldn't have lawyers. I'm also now imagining how unimpressed an NTSB investigator would be if there was an accident, and they checked my logbook to find I had been logging PIC time without a valid medical. Since the other pilot isn't logging time, it seems they only would have my word that I wasn't also acting as PIC. Anyway I hope you have a nice weekend :)

@757toga Interesting. I felt their analysis is wrong for another reason- it relies on 61.51(e)(1)(iii), which states that it only applies when the regulations require two or more pilots. And if the regulations require two pilots, I really don't see how it could possibly be legal for pilot A to be one of the required pilots without a medical.

Regarding the hypothetical NTSB investigation, the first question any investigator will ask is "who is the PIC?"  To which your friend will be obligated to raise his/her hand.  Second question will be "who was flying?", but it will be your friend in the hot seat first...

@757toga Yes, that is specifically set out as allowed under the definition of "pilot time."

It is pretty simple. If your medical is not valid, you can not be pilot in command.
You can go flying with your friend, but he will be pilot in command, and he will log the time.

I agree you cannot act as PIC without a current medical, but sole manipulator?

I keep forgetting about FAA “sole manipulator” since I am not FAA licenced. My guess is no to “sole manipulator” since his medical is not valid and he is not receiving training.

Yes.
Regarding logging PIC time, 14 CFR § 61.51(e) states in part:

(1) A sport, recreational, private, commercial, or airline transport
pilot may log pilot in command flight time for flights-
(i) Except when logging flight time under § 61.159(c), when the pilot
is the sole manipulator of the controls of an aircraft for which the
pilot is rated, or has sport pilot privileges for that category and
class of aircraft, if the aircraft class rating is appropriate;
(ii) When the pilot is the sole occupant in the aircraft;
(iii) When the pilot, except for a holder of a sport or recreational
pilot certificate, acts as pilot in command of an aircraft for which
more than one pilot is required under the type certification of the
aircraft or the regulations under which the flight is conducted; or

You really don't need to go any further than that.
You cannot "perform the duties" or "act as PIC" without a current medical certificate, which is stated clearly in 61.23(a)(3)(ii).  The FAA breaks PIC duties out separately from "sole manipulator" and your friend must be act as PIC.  However, if you are a rated pilot flying the airplane you can log the time while you are sole manipulator per 61.51(e)(i).

Seems like poor legal advice to suggest one doesn't need to check the definitions of terms used, when "flight time" and "pilot time" are both clearly defined in the regs. I'd be open to an argument that my analysis is in some way flawed, but just ignoring the definitions seems rather cavalier.

@Chris-RegenerateResponse, I am not offering legal advice, and I'm not ignoring definitions, this one just happens to be self contained.  In this context, PIC time is defined as "when the pilot is the sole manipulator of the controls of an aircraft for which the pilot is rated".  If a medical certificate was also required it would say that just like it does when describing requirements for "acting as PIC" in 61.23(a)(3)(ii).  It is well established that acting as PIC and logging PIC as sole manipulator are distinctly different.

...and I am no more cavalier for seeking a permissive interpretation than you are irrational for seeking the most restrictive one.  You are free to disagree, and I always welcome constructive feedback, but I'm not alone here.  Let the votes be cast...

Just stating my thoughts. The full sentence (chopping off the irrelevant parts that apply only to sport pilots and part 135 operators) is "A sport, recreational, private, commercial, or airline transport pilot may log pilot in command flight time for flights when the pilot is the sole manipulator of the controls of an aircraft for which the pilot is rated." I don't think that you can interpret this sentence without reference to the definition of "flight time." But as far as I can tell there is no FAA interpretation directly dealing with this, so we can agree to disagree.


text:
Victor route using an unusable sector of a VOR
V155 is an airway that terminates at the BROOKE VORTAC on the 214 radial.

The chart supplement says all of its radials are unusable (radials 001 thru 360). How could this be a valid route since no radials are usable to be able to navigate to this VORTAC after the changeover point?

When a victor airway is established, FAA flight test pilots verify the VOR can provide adequate / acceptable navigation along that route through (1) the halfway point to the next VOR or (2) changeover point.  Since V155 uses BRV it has undoubtedly been flight tested to within acceptable tolerances.  If the VOR is unusable after flight testing, a NOTAM will be issued for the VOR and most likely a FDC NOTAM issued for the airway.
The chart supplements lists navigational issues for the VOR within it's service volume as detailed in the AIM (1-1-8)

b. A NAVAID will have service volume restrictions if it does not conform to signal strength and course quality standards throughout the published SSV. Service volume restrictions are first published in Notices to Air Missions (NOTAMs) and then with the alphabetical listing of the NAVAIDs in the Chart Supplement. Service volume restrictions do not generally apply to published instrument procedures or routes unless published in NOTAMs for the affected instrument procedure or route.

Looking at the low enroute chart for Brooke VOR.

V155 SW bound has a change over point 10 NM past the VOR on a 53 NM leg.
V286 NW bound uses the VOR for 20 NM before a change in heading precipitates the use on a different VOR
V286 SE bound has a change over point 22NM past the VOR while the other VOR is used for 66NM.
It is also interesting that OJAAY intersection is defined by the CSN VOR 39NM away instead of the Brooke VOR at 10NM away.

Good answer.  Might it be worth mentioning that the changeover point, normally midway, is 10 miles from BRV on a 53 NM leg?  Seems like this is a good illustration why that is...

@757toga, ok then, back to the question…. I suppose we might expect a change to the chart next cycle.


text:
What is the formula to calculate minimum knots groundspeed hydroplaning will occur?
Many articles on hydroplaning cite the following formula on the minimum speed necessary for hydroplaning to begin:
$$
9 * \sqrt{\text{Tire Pressure}} = \text{Maximum Hydroplaning Speed}
$$
Is this the correct formula to calculate knots groundspeed using PSI for tire pressure?

The formula that you have mentioned is correct but with a slight alteration. The expression on the left-hand side of the equation should be equal to $\text{Minimum Hydroplaning speed}$, meaning that at or above this groundspeed, hydroplaning is possible. Therefore, the correct formula for an aircraft rotating wheel is:
$$9\sqrt{\text{Tire Pressure [PSI]}}=\text{Minimum Hydroplaning speed [knots]}$$
or, with a different tire pressure unit:
$$34\sqrt{\text{Tire Pressure [Bar]}}=\text{Minimum Hydroplaning speed [knots]}$$
In order for a tire to lift from the surface of the runway and hydroplane, certain conditions must be met. These are:

The depth of the water on the runway must be greater than the depth of the tire tread. If this essential condition is not met, the hydroplaning cannot occur.
The minimum hydroplaning speed is also dependent on whether an aircraft tire is rotating or non-rotating. The given formula is only valid for a rotating aircraft wheel (e.g. takeoff). If a wheel is not rotating (e.g. upon landing or locking up), a different formula is applicable:
$$7.7\sqrt{\text{Tire Pressure [PSI]}}=\text{Minimum Hydroplaning speed [knots]}$$
If a wheel is not rotating - it is more prone to hydroplane. This makes sense because the grooves on the tire are no longer working effectively to expel the water from beneath the tire.
The mentioned formula is Empirical, meaning that it is based on observations and not mathematically deduced from laws of physics. This is also why the dimension of the expression of the left-hand side is not equal to the dimension of the expression of the right-hand side of the equation for this formula. Notice that the measurement unit for one side of the equation is $\sqrt{\text{PSI}}$ and for the other side is $\text{knots}$

In order to avoid hydroplaning upon touchdown (non-rotating wheels), the crews are often instructed to perform the so-called "positive landing" - meaning that you don't make a gentle (smooth) touchdown, but instead, a firm contact to the runway surface so that you immediately penetrate a layer of standing water on the runway. The use of ground spoilers increases the weight on the wheels to more easily penetrate the layer of standing water and improves braking capabilities, so the use of ground spoilers in this kind of situation is definitely desirable. Light brake pressure is advised in order to not lock the wheels.

I agree the formula provides for the speed above which brakes should not be applied when landing on a wet runway.  In my sleepiness last night, I debated using minimum or maximum.  I can see your reasoning.  I reasoned from the pilot perspective as the minimum speed required for hydroplaning to start or maximum speed I want to press on the brakes.

Yes, it is the same thing, just a matter of perspective, I hope I answered your question well!

I thought it was great.  Do you have a reference for the information, though?

Sure. The majority of the information is from the ATPL Book 12 - Operational Procedures. You can check any ATPL Book 12 from any provider (former JAA versions, current EASA versions, CAE, Oxford and etc, they will all have the same topic discussed. Some will go into more detail and some in less). The information is mainly provided from Chapter 21 - Contaminated Runways, subsection - Aquaplaning (Hydroplaning). Part of the answer is also written from my experience.

Great.  Thanks.  I appreciate the information.


text:
What's the reason for not allowing private pilots to get paid for their services?
As per a recent answer:

A Private Pilot certificate removes a lot of the restrictions
of the recreational cert. You're no longer restricted in where you can
fly*, the number of passengers you can carry, can fly at night, and
are even allowed some (very limited) business use. You still can't be
compensated for being a pilot, though.

A Commercial Pilot certificate allows you to work as a pilot,
and fly for compensation or hire.

But... why does this distinction exist? If you can be trusted to fly safely on a Private Pilot license, why can't you be trusted to do the exact same thing while getting paid?

Nobody can be trusted to fly 100% safely. It doesn't matter if you are a brand-new private pilot or a 10000 hour ATP, flying always involves some level of risk. This risk hopefully decreases as pilots gain more proficiency, and the logic is that the more you are exposing the general public to risk, the lower that risk should be.
This is also why different levels of medical certification exist- the FAA accepts that is reasonable to accept a greater level of risk to yourself and your family and friends than it is to expose the general public to.
There are also some additional risks directly involved with receiving compensation. A "mission mindset," where a pilot may accept unacceptable risks because they are too focused on their mission, is already a contributor to many general aviation accidents even when compensation is not involved. It goes without saying that being paid to do something adds additional pressure that may influence any pilot to decide to fly when a no-go decision would be more appropriate.

Do you know if lobbying by pilot unions had something to do with it as well?

@JonathanReez, I doubt there's any need to lobby - it really isn't very controversial to require a higher standard of a professional.  Would you hire a Private Pilot over a Commercial Pilot?

@MichaelHall yes, I definitely would, as I've previously taken several flights with a friend of mine who has a Private Pilot license. Whether or not I'm paying for the flight doesn't change how I perceive the level of risk. If it's acceptable free of charge it's also acceptable when I'm paying and vice versa.

Fair enough then, but there's a level of trust and knowledge you have with your friend that the general public doesn't have with a stranger.

Anyway, there are plenty of other businesses that require a higher standard of training and certification for professionals vs amateurs, most with far less risk to property and life at stake than piloting.  Heck, you can go to jail for offering free haircuts to the homeless without a barber's license!  Most things need to be earned... so why would you advocate for granting full commercial privileges to a fresh private pilot?

@MichaelHall sure, but it doesn't mean it should necessarily be banned? If you don't trust a fresh pilot, you don't fly with them. I just don't see why the exchange of money makes any difference whatsoever.

But the public doesn't know that.  How would you know whether or not to trust a pilot you've never met?  There is a general presumption that someone advertising commercial services (of any sort) has been vetted somehow, and is qualified and competent to do what they advertise.  What part of that do you not understand or agree with?

@MichaelHall I've read similar arguments 10 years ago about Uber :-) People were fuming about how we need all these professional drivers carrying passengers, because somehow the exchange of money makes it a lot less safe. Or people would claim that a pro driver can beat Google Maps, so non-pros should not be allowed to pick up passengers. Luckily that debate has now been settled. I'm trying to understand if this is merely a lobby-influenced Uber vs. "Pros" kind of debate or if things are actually different in aviation.

That's a reasonable comparison, but don't expect the FAA to change their minds on this one.

@JonathanReez Here in the UK uber drivers are quite reasonably held to the same standards as other taxi drivers, they aren't exempted.

@Dan yes the UK/London has some of the strongest taxi lobbyists in the world so they haven’t fully adapted the Uber model. Most other countries did though and taxi mafias are now a thing of the past.

@JonathanReez Flying via airlines is the safest form of transportation there is. General aviation is much much less safe. It's a much bigger difference than between taxis and uber drivers.

That one is not so much a decision of the FAA, but rather the power vested in Congress, under Article 1, Section 8 of the US Constitution, giving it broad discretionary power to regulate interstate and international commerce.  As such, Congress can have a very large reach in these matters, and demand that pilots who are part of such commerce be subjected to higher standards of scrutiny, than people flying for purely recreational purposes.
Now exactly what a higher level of aviator skill for interstate commerce flying has to do with requiring a pilot be able to perform interesting but stupid parlor tricks like lazy eights and watered down chandelles is beyond me.  The majority of commercial jobs as a pilot are out of reach until you obtain an airline transport pilot’s license as well.  Ultimately the real reason that you cannot fly for compensation or higher (or may do so in a very limited capacity - see §61.113) is because the government says so.

Unfortunately this narrow interpretation of the Commerce Clause is long obsolete. The Supreme Court ruled all the way back in 1942 that even someone who doesn't participate in commerce can still be subject to Congressional regulation. So the Feds could easily restrict non-commercial aviation as well if they so desired.

I am focusing more on commercial aviation than recreational aviation with this post.


text:
Do the FAA provide help on airworthiness of ultralights?
The answer to the question Can my plane get off the ground? has the comment:

I'm going to get it checked by the faa

Part 103 for Ultralights says that:

(a) Any person operating an ultralight vehicle under this part shall,
upon request, allow the Administrator, or his designee, to inspect the
vehicle to determine the applicability of this part. (b) The pilot or
operator of an ultralight vehicle must, upon request of the
Administrator, furnish satisfactory evidence that the vehicle is
subject only to the provisions of this part.

but also that

(a) Notwithstanding any other section pertaining to certification of
aircraft or their parts or equipment, ultralight vehicles and their
component parts and equipment are not required to meet the
airworthiness certification standards specified for aircraft or to
have certificates of airworthiness. (b) Notwithstanding any other
section pertaining to airman certification, operators of ultralight
vehicles are not required to meet any aeronautical knowledge, age, or
experience requirements to operate those vehicles or to have airman or
medical certificates.

That doesn't sound like the sort of airworthiness consultancy that the comment implies.  In the UK you could ask the British Microlight Aircraft Association to look over your design.  Do the FAA provide that sort of service?

The BMAA is a very different kind of organization from the FAA.

@DJClayworth  Exactly, that's why I mentioned it.

"get it checked" is more likely to mean have it inspected vs "consultancy" IMHO.

(a) Any person operating an ultralight vehicle under this part shall, upon request, allow the Administrator, or his designee, to inspect the vehicle to determine the applicability of this part. (b) The pilot or operator of an ultralight vehicle must, upon request of the Administrator, furnish satisfactory evidence that the vehicle is subject only to the provisions of this part.

This inspection is limited to checking that an ultralight is in fact an ultralight. For a powered ultralight, this means no more than 254 pounds empty, single seat, no more than 5 gallons of fuel capacity, etc. Once it's determined to be a legal ultralight, the FAA's interest in its airworthiness (or lack thereof) ends.

The FAA doesn't want to know about your legal ultralight. There's no "FAA inspection" of them not are they required to be registered or issued an airworthiness certificate.
Illegal ultralights, especially ones that can carry a passenger, will get their attention and fines issued.
Good luck.


text:
Do you need a commercial license to make money as an aerobatic pilot?
Is it required that you possess a commercial pilots license in order to:
a) win cash prizes at competitions
b) receive payment from sponsors when advertising on the plane wing for example
c) be paid to perform at an air show?

The following applies to US law. I expect it is largely similar to UK law in this respect, but obviously you shouldn't rely on FAA interpretations to interpret CAA regulations.
From the Comstock interpretation:

Prize money awarded on the basis of competition is not compensation.

So (a) is allowed without a CPL.
(b) is a grey area, and would likely depend on the totality of the circumstances. An agreement where a company agrees to pay you to paint an advertisement on your plane, regardless of how much, where, or even if you fly it, is probably legal. If the company wants to exert any operational control over the flights, it is almost definitely not legal. In any case, you would want to consult a lawyer experienced in aviation before agreeing to any such contract.
(c) is illegal without a CPL. A private pilot cannot act as pilot in command for compensation or hire unless one of the exceptions in 61.113(b) through (h) applies. It's hard to see how any of the exceptions there could apply.

I don't totally disagree with your answer to (c), but it's a pretty absolute statement, (ruling?) that begs a citation.  Because most CFRs reference carrying "passengers or property for compensation or hire".  This is certainly not that, which makes it a good question in need of some further explanation...

@MichaelHall 61.113(a) reads "Except as provided in paragraphs (b) through (h) of this section, no person who holds a private pilot certificate [...] nor may that person, for compensation or hire, act as pilot in command of an aircraft." Unless one of the exceptions apply, it is illegal for a PPL to act as PIC for compensation even without passengers or property. None of the exceptions in 61.113(b) through (h) applies here. Or at least I don't see how- the closest is the "incidental to business" part and it's hard to see how that would apply here.

Fair enough.  I might recommend adding that to your answer though.


text:
61.113 - As a private pilot, can I be reimbursed for flights on which I conduct scientific measurements for my job/school?
I'm a grad student working on some research that is funded by grants awarded to my advisor at an American university.
We perform scientific measurements using GPS receivers and are considering collecting some data from an airborne platform. (These measurements are completely passive. They simply record signals from any available GPS satellites visible to the receiver).
I happen to be a private pilot (+instrument) and was wondering if I could rent a plane, carry one of these receivers onboard to take measurements, and be reimbursed for the flight afterwards.
§61.113:
(b) A private pilot may, for compensation or hire, act as pilot in command of an aircraft in connection with any business or employment if:

    (1) The flight is only incidental to that business or employment; and

    (2) The aircraft does not carry passengers or property for compensation or hire

I believe such a task would certainly be "incidental to my employment" and our organization. The flight(s) would be solo. I suppose I am carrying property (the GPS receivers), but the intent is not to transport it for compensation or hire... I suppose (b) is what I'm unsure about...
Would love some additional thoughts on this.
Thanks!

It's very straightforward. The GPS receivers are their property, and if you are compensated, then you are carrying property for compensation.
Ask yourself this: would my advisor still reimburse me if I did the exact same flight without the receivers aboard? Of course not. So you are being compensated specifically to carry property. You say that the intention is not to "transport" it, but the phrase used in 61.113 is "carry," not "transport." There is no doubt you will be "carrying" the receivers, and that you are only being compensated because you are carrying them.

Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on [meta], or in [chat]. Comments continuing discussion may be removed.

If you were to run afoul of 61.113 on this matter it would NOT be for carrying the equipment.
The words “carry” and “transport” are not uniquely separate or different.  Nor are they specific to aviation – Freight carriers in other transportation industry modes use the same terminology.
Carry: “to transport goods from one place to another.”
Per the White interpretation of 1995:

“The Agency has consistently interpreted Section 135(b)(4) so that if an aircraft lands at a site other than its origin, the aerial photography or survey exception does not apply*. This is due to the fact that the flight takes on the "dual purpose" of both aerial photography or survey and transporting passengers from one point to another for compensation or hire.”  (emphasis is mine)

If you take off and land at the same airport you are NOT transporting the equipment from one place to another, therefore you are not engaged in private or commercial carriage.  The mere presence of the equipment in the aircraft does not meet the required definition for carrying it.  The purpose of the flight is to use the equipment, not transport it.
The harder part might be determining whether the flight is incidental or not. To help us determine this we can look to the Perry interpretation which states in part:

...an individual must hold a commercial pilot certificate in order to act as pilot in command of an aircraft involved in an aerial photography business.  To reach that conclusion, the FAA examined whether the photography flights would be incidental to the pilot's business, and found that the "proposed aerial photography business is not an activity, completely unrelated to aviation activities, in which a pilot certificate would be irrelevant to the fundamental character of the business."

That last sentence in quotes is a mouthful, but in short it would seem to say that if there were alternate ways of gathering the GPS data you seek then flying would be incidental.  (i.e. could you gather the same data using these receivers in a car?)  If the equipment is aviation specific you might not be able to justify flying it as incidental.
As always, you would be wise to consult with an aviation attorney or local FSDO, especially if this will be an ongoing thing.

I'm not convinced. Your argument would seemingly apply equally well to a flight where you are carrying around other photographers, where they take the pictures, and then you return to the same airport. Just like this case, the purpose is not to transport them, but to take pictures. But the FAA declares that case to be unequivocally illegal in the White interpretation. The part 135 bit is a red herring- private pilots are not allowed to do anything under the aerial photography or survey exceptions (described in part 91.501), unless one of the exceptions under part 61.113 also applies.

In short, 61.113 is a restriction on the pilot and 91.501 talks about restrictions on the operation. Both have to apply in order for a private pilot to legally operate under part 91. 91.501(d) is good to read to see the difference- it describes a lot of things that are legal to be paid for under part 91 that are definitely not legal for a private pilot.

@Chris, 91.501 applies only to "the operation of large airplanes of U.S. registry, turbojet-powered multiengine civil airplanes of U.S. registry, and fractional ownership program aircraft of U.S. registry". I.e., airplanes you need a type rating for, not typically flown by private pilots. Not applicable to renting a piston single or light twin. And yes, I agree that chartering other photographers around would not be incidental.

The topic of being "incidental" does not come up in the White interpretation. If the photography is not incidental to the business, it's illegal whether or not other passengers are aboard (as described in the Perry interpretation you linked). The critical difference between the legal and illegal flights described in the White interpretation are whether passengers are carried. Since the phrase is "carry passengers or property," I don't see how carrying university property versus carrying passengers can be distinguished legally.

91.501 may only apply to large or turbojet powered planes, but it's also where the "aerial work" exception is mentioned in part 91. The section quoted in the White interpretation that mentions this exception, 135.1(b)(4), is no longer in the FARs at all. In any case, it's hard to see how anything from part 135 could possibly have relevance to a private pilot.

@Chris, Interesting that you point out that 135 is irrelevant but 91.501 is?! Let’s agree that neither applies in this case. Anyway, the excerpt I pulled from the White interpretation wasn’t intended to show applicability of 135, instead I used it to support FAA and industry standard interpretation and use of the term carry, and its variations carrier, and carriage. That formed the basis of your answer, and it just doesn’t fit in this scenario.

I agree that 91.501 is irrelevant. But I just don't see how having photographers on board taking photos versus having equipment on board taking data are distinguishable from a legal standpoint.

@Chris, Maybe they aren’t, that’s why I recommended consulting a lawyer or FSDO. But the White interpretation is clear enough to me on this point - you can take your own photos, but not get paid to haul photographers.


text:
What does this hand gesture of fighter jet pilots mean?
I am trying to understand more of the gestures fighter jet pilot use. I have seen this gesture many times:

Does anyone know what this gesture mean? Are there any good resources about the gestures used by fighter jets? I can't find information about this.

It is interesting that we have a tag for "radio-communications", but not one for other forms of communications.

I have also seen more signs like those can someone pls paste a link to meanings of them?☹

@JAS39Gripenfanimnotapilot, there's a link in my answer below.

It is the signal to perform a fuel check.  (Actually: "How much fuel have you?")
The hand mimics drinking from a bottle, and when given by a formation flight lead it is intended to prompt the wingman to respond with a number of fingers to indicate fuel remaining in hundreds of pounds.
There are several pages of inter-flight signals in table form found in the NAVAIR 00-80T-113, "AIRCRAFT SIGNALS NATOPS MANUAL".  (For US Navy, the USAF likely has a similar document...)  A copy can be found here:  SIGNALS NATOPS
This particular signal is found on page 1-8 and is reproduced below.  (Note - the pinky seen in the photo isn't specified, but is generally used to ensure that the signal isn't confused with a closed fist)

Very interesting! Thank you for your clear answer!

I see that the NATOPS literally writes it that way, but how is "How much fuel have you?" not incorrect grammar? Is that some phraseology quirk I'm unaware of?

@MrArsGravis it's not incorrect but sort of old fashioned. see also https://ell.stackexchange.com/questions/101667/use-of-have-in-questions-do-you-have-or-have-you

I'd looked it up in a the Oxford Reference Grammar in the meantime and it also concurred that it is still a somewhat accepted form in BrE. If this Ngram is to be believed, it actually seems to have been the dominant form, at least in written English, up to the mid-20th century (I was expecting it to have died out a century earlier): https://books.google.com/ngrams/graph?content=Have+you+a%2CDo+you+have+a&year_start=1800&year_end=2000&corpus=en-2012&smoothing=3

It sounds better if you ask in a Yoda voice...

With the pinkie out, it means "Is it time for tea?"  Used by British armed forces.

@WayneConrad Are they required to signal back "yes"?

@Ivo, "it's not incorrect but sort of old fashioned"  More old fashioned would be "how much fuel havest thou?"


text:
Why is calibrated airspeed (CAS) greater than indicated airspeed (IAS) at lower airspeeds?
As can be seen in the correction chart, the difference between the IAS and CAS is greater at lower indicated airspeeds, however when the IAS increases, the difference is minimal.

Only from the title on hot network questions, I though it was referring to close air support, with the answer being you have more time on target. :))

Especially since this is on HNQ (Hot Network Questions), could you please edit to define at least the less-well-known terms like CAS (in the question body; the title can be short)?  I know that IAS is Indicated AirSpeed (and the question title does define it) but I don't remember coming across CAS.  (or anyone else could edit, perhaps @vsz)  I know I can just look it up, but so will multiple future readers. (Is IAS without instrument error the same as CAS? was in the "related questions" sidebar: Calibrated AirSpeed.)

Near stall speed the angle of attack is high and the pitot tube is pointed less into the relative wind. Thus it registers less pressure and shows a lower value.
It also makes sense to calibrate the airspeed indicator so it is most accurate at speeds in the middle of the envelope where you spend the vast majority of your flight time.

As a non-pilot, it seems to me that it would make the most sense to calibrate it for the most critical parts of flight - take off & landing, instead of cruise. Again, IANAP...

@FreeMan As long as the airspeed indicates consistently in these phases (it does), you don't really care about the exact values. This calibration is mostly useful for determining your true airspeed for determining how long it will take you to get to your destination. Being off by 20% for a few seconds during the flare doesn't really make a significant difference.

Ah, that makes sense. thanks!

Therefore, the table shown in the question is technically valid only for 1g flight conditions. At 2g, for example, angle of attack would higher for a given speed.


text:
Foreign Dual on USA log book?
I am a commercial helicopter FAA pilot with a USA logbook. I specify it's USA because it is in english and as you know with available entries to file that I believe mean something else in Argentina.
My question is if I can log dual time “instruction” in this book, because im a student working on a airplane rating.
Will this dual time count in the USA considering it's dual on a LV tail number?
And also any PIC time during required solo.
The problem is here for PPL you don't get a log book until you finish. But I already have this USA one and plan on going to the USA before finishing the rating or after.

Yes, you can log it. From 14 CFR § 61.41(a):

A person may credit flight training toward the requirements of a pilot certificate or rating issued under this part, if that person received the training from [... a] flight instructor who is authorized to give such training by the licensing authority of a foreign contracting State to the Convention on International Civil Aviation, and the flight training is given outside the United States.

You are only allowed to log training. They can't endorse you for a practical test or a rating or anything:

A flight instructor described in paragraph (a) of this section is only authorized to give endorsements to show training given.


text:
IFR plan only with GPS
I'm right before CFII checkride
I understand that if it is without WAAS, I need navigational equipment other than GPS because I can flight plan based on GPS either destination or alternate.
However, If I don't need an alternate for good weather and just plan to use GPS approach at my destination is it allowed I can flight plan with failed VOR?
91.205 (d) navigational equipment for route to be flown means just navigational equipment (not necessarily ground-based one) and If I don't need alternate I think I can flight plan legally on GPS,,, but I'm not sure. I wonder if "either destination or alternate" means if I don't need an alternate, still I have to possess equipment other than GPS ...  english is so difficult for foreign student. would you guys help me?

No, you need an alternate source of navigation to use a non-WAAS GPS at all. From AIM 1-1-17(b)(2)(a)(2):

Aircraft using un-augmented GPS (TSO-C129() or TSO-C196()) for navigation under IFR must be equipped with an alternate approved and operational means of navigation suitable for navigating the proposed route of flight. (Examples of alternate navigation equipment include VOR or DME/DME/IRU capability). Active monitoring of alternative navigation equipment is not required when RAIM is available for integrity monitoring. Active monitoring of an alternate means of navigation is required when the GPS RAIM capability is lost.

In short, not only must you have backup navigational equipment, you can only fly routes that you could navigate even if your GPS fails.


text:
Where is the VFR Day certification List
Where can I find the VfR day certification instruments and equipment for which my aircraft was certificated?
Is this 91.205? I looked through the POH it mentioned Part 91.
Is it saying that the aircraft is only airworthy IF those instruments are operative apart from ADs,Maintenance times?
If The instruments are inoperative then the airplane cannot fly?
But if the instruments are not listed in 91.205 and does not have an AD
Would I just use a placard to indicate it’s inoperative and make a notice to maintenance?
Is that the full procedure?

Yes. Refer to 91.205(b) for VFR (day).  Part 91.213 addresses Inoperative equipment. transponder and ADS-B out equipment may also be required. Please narrow your focus as ASE is based on one question at a time, not 4 or 5.

You need everything in 91.205(b), but your POH should have an equipment list. Anything marked as required in that equipment list is also required, as is anything listed as required on the Type Certificate Data Sheet for the aircraft type. These requirements may be altered by alterations to the aircraft- for instance, if you replace your vacuum instruments with a pair of Garmin G5, the STC permits you to remove the vacuum system. Airworthiness Directives may also add required equipment.
Once you've determined that equipment is not required, you need to disable it and placard it as inoperative or have it removed per 14 CFR § 91.213(d)(3).
The above assumes you are not authorized to use a Minimum Equipmemt List for that aircraft. If you are, you have to follow that.
Finally, you can apply for a special flight permit to operate the plane while you are lacking some required equipment. This is frequently used to transport planes to somewhere they can be repaired.

Ok so I Should follow the equipment list. That should be the comprehensive equipment list in my POH? And all of the instruments listed in the Comprehensive list should be apart of the TCDS? In the event that I replace an instrument such as the vacuum system, The STC and the AD would require meant to  That would permit me to remove the Vacuum system.

Ok so I Should follow the equipment list. and that should be the comprehensive equipment list in my POH? 2. All of the instruments listed in the Comprehensive list should be apart of the TCDS? 3.In the event that I do have to replace an instrument such as the vacuum system, The STC and the AD would may be required to remove the system entirely.   Lastly, if the equip is not apart of the Comprehensive list and 91.205 and it is inoperative, I would label it inoperative?

You need equipment if it is listed as required in any of 91.205, the POH, the TCDS, or any applicable ADs. STCs can remove a requirement, essentially amending the type certificate.


text:
What’s the math on finding your Freezing level?
If the std temp lapse rate is 2c per 1000, and the freezing level is 0c.
If at the sfc my temp is 4c wouldn’t the freezing level be at 2,000?
If so I calculated this using a long method. Is there a formula that I can use to calculate this easily?

You just did...  You calculated it easily.  Seriously, what easier method might there be?  I'm just not sure what you are asking.

Some persons would divide 2 by …. The way I did it was write out each temp per altitude… isn’t there a shorter way?

Current Temp / 2 * 1000 + Field Elevation

@wbeard52 thank you. This is what I was looking for.

@Michael hall  wbeard52 provided the formula that I was looking for.

OK, that's kinda like converting "two plus two" into "2+2", but if it answered your question then good.  @wbeard52, you should post your answer as an answer, not a comment.

Here's how you can figure out the formula. You know that the temperature drops $2^\circ$ per thousand feet. You can represent this mathematically as:
$$ \text{Temperature} = \text{Surface Temperature} - 2^\circ\times\text{Altitude in 1000s of feet} $$
You want to find the altitude where the temperature is zero, so set $\text{Temperature}=0$:
$$ 0 = \text{Surface Temperature}- 2^\circ\times\text{Freezing Altitude in 1000s of feet} $$
You know the surface temperature and want to solve for the freezing altitude, so you want to get altitude on one side of the equation alone. This can be done in two steps:

Add $2^\circ$ times the altitude to both sides of the equation:
$$ 2^\circ\times\text{Freezing Altitude in 1000s of feet} = \text{Surface Temperature} $$
Divide both sides by $2^\circ$:

$$ \text{Freezing Altitude in 1000s of feet} = \frac{\text{Surface Temperature}}{2^\circ} $$
It might be a good idea to read through an algebra book and work through some exercises, or take a course if possible. You don't need to know a lot of math to be a pilot, but you do need to know some.

According to the International Standard Atmosphere (ISA), temperature drops of 0.002°C per ft (0.0065°C per m) till a height of 36'000 ft (11'000 m). Knowing the temperature at SFC, the relevant math is quite simple:
$T_{@height} = T_{@sfc} - 0.002 \times height $
with temperatures in °C and height in ft.
If you want to find at which height a specific temperature is reached, you simply have to rearrange the terms of this formula to get:
$height = (T_{@sfc} - T_{@height}) / 0.002$

You want to know for example at which height the temperature is 0°C? You just set $T_{@height} = 0$ and you get $height = T_{@sfc} / 0.002$. In your example where $T_{@sfc} = 4$ we get $height = 4 / 0.002 = 2'000$ ft.
You want to know at which height the temperature is 3°C? You just set $T_{@height} = 3$ and you get $height = (T_{@sfc} - 3) / 0.002$. In your example where $T_{@sfc} = 4$ we get $height = (4 - 3) / 0.002 = 1/0.002=500$ ft.
And so on.

P.s.: sorry for being late but I had already prepared this answer and found no more time to post it.


text:
Should turns always be standard-rate?
I know that the turn coordinator has markings that allow you to turn at a particular rate, so you can use the TC and a clock or stopwatch to turn a particular number of degrees. Are you always supposed to turn with the wings on one of these marks, or is that only necessary when you need to use a clock to measure your turn?

The Turn Coordinator index marks denote a standard rate turn. Standard rate is 3 degrees per second, meaning it takes 2 minutes to fly a full circle.  It's also called a "2 Minute Turn" or "Rate 1 Turn".
The bank angle required to achieve a standard turn rate varies with true airspeed, and you can estimate it by dividing your TAS by 10, +7. So, at a TAS of 100 kt, a seventeen degree bank angle gives more or less a Rate 1 turn.
Rather than have to estimate the bank angle to use in your head, you just use the Turn Coordinator to tell you when you are at the required bank and save the mental formula for when the Turn Coordinator fails.
Generally, standard rate turns are used for IFR flying, most turns when on instruments being flown at the standard rate. On airplanes with Flight Directors, the FD will command bank angles that provide a standard turn rate at lower speeds, and the autopilot (which just does what it is told by the Flight Director) will turn the airplane at standard rate (at higher speeds and altitudes, turn rates are reduced due to bank angle limitations).
Outside of IFR flying, there isn't really any need to stick precisely to a standard rate turn if you're just blundering around on a nice day. An exception to this might be flying without a directional gyro, and you want make precise turns from one heading to another, and holding the standard rate in the turn allows you to time when to roll out of the turn and be reasonably close.
Timed turns is a skill that pilots taking instrument training have to master for flying "partial panel", where you have no directional gyro and are flying by wet compass only. When the compass is dancing and slewing every which way while turning, it's pretty much useless until you settle into level flight, and a stopwatch can come in handy. Even just counting "one thousand two thousand..." for the period of the turn will get you in the ballpark if you hold the standard turn rate and can count seconds with reasonable accuracy.

It’s an interesting one concerning IFR flight. In my experience, SOPs for 737s state limiting angle of bank (with the limiter) to 25°. Which actually is a lesser than rate 1 turn for practically all of the flight, including procedural instrument approaches (can be difficult to force deceleration to 180 knots).  (Also bank angle limiter turned down to 10° for flight above FL300)

I should have mentioned that this was for slower speeds. Yes FDs for jets will use much lower turn rates.

Fly the aircraft however you want to fly the aircraft... if you want a really slow turn, put in a few degrees of bank.  If you want to crank it around, roll it to 60 degrees and enjoy the 2 G's.  There's a time & a place for each of these, and everything in between.
If you have a need to ("are supposed to") fly a standard rate or a half standard rate turn, then use the marks on the turn coordinator.  If that's not required, and usually it isn't, then there's no need to attempt to match that rate.
There are cases when a standard rate turn is desired; an ASR approach comes to mind, which is a little rare these days.  There are probably others, beyond timed turns (which is also a valid example).

Don’t all published procedural approaches assume standard rate turns, not just ASR? cf. PANS-OPS.

Are you always supposed to turn with the wings on one of these marks,
or is that only necessary when you need to use a clock to measure your
turn?

In the VFR context, no one ever feels compelled to limit turns to standard rate, and in practice turns are almost always conducted at a much higher rate.
I have completed a powered pilot's license as well a glider pilot's license in the USA, (private in each case) and I would be willing to bet large amounts of money that my total time engaged in turns at standard rate (or lower) throughout the entire duration of my training, as well as throughout additional flights after completion of training, does not exceed ten minutes.


text:
How is Vx speed and Vy affected when climbing?
If my speed for best angle of climb is 60 and rate is 79, if I kept a 500 fpm climb to my cruise altitude of let’s say 4500, would those speed change?
The flights are being done on separate occasions.

Related: https://aviation.stackexchange.com/q/73997/34686 , https://aviation.stackexchange.com/q/53081/34686

If you are targeting a specific vertical speed and adjusting power to maintain 60 and 79 knots respectively, just know that you are not climbing at Vx and Vy.  That should go without saying, but…

I'm sorry, I didn't see the part of the question that reads "if I kept a 500 fpm climb to my cruise altitude".  I thought you were just asking whether Vx and Vy changed with altitude, and I answered accordingly.  Question appears to be a mishmash of something about how Vx and Vy change with altitude, and something else about what speed you have to fly at to get a 500 fpm climb rate and how that changes with altitude.  Needs more clarity.

Do you want to know the speed that gives the best climb angle given that you are maintaining a 500 fpm climb rate?  Obviously you will fly at max power, and obviously you get the best climb angle at the slowest speed that will achieve your target climb rate.  (So if you can get the target climb rate on the "back side" of the power curve rather than the "front side", you'll fly on the "back side".)  Are you trying to craft a question about that particular situation, and how the speed you end up flying changes with altitude? But if so, why introduce Vy into the picture at all? Needs clarity.

It's very confusing to ask something about Vy (speed for best climb rate) in the context of a scenario where the climb rate is constrained to a given value (e.g. 500 fpm).

Youngpilot, at the risk of more piling on, there are three parameters in your question:  Airspeed, climb rate, and power setting.  You can fix two of these three, the third will vary.  Choose any two.  So my point is that if you choose to climb at 500 fpm at 79 Kias, you will probably have to pull some power back.  If you are climbing at less that full power you are not climbing at your best rate - Vy assumes full power, and pitching for airspeed.  I have downvoted the question because you need to clarify what you are asking about.

Yes the speeds would change-- because they must converge at the aircraft's absolute ceiling, where no more climbing is possible.  Vy (best climb rate speed) decreases more than Vx (best climb angle speed) increases, but they both change.
If thrust were absolutely constant with altitude, then Vx would remain constant.

Both Vx and Vy vary somewhat by density altitude.  Check your POH.  It should have a table.
It doesn't vary much, though.  Somewhere in the neighborhood of 7 kts per 10,000 feet.

I assume you ask for a piston-powered airplane with constant speed propeller. Next, I assume you want those speeds as IAS, so you need not correct for density effects. Then the grah below shows the general behavior of the optimum climb speeds for different power loadings (ratio of thrust over weight).

Climb speed polars (green) over indicated airspeed for different power loadings. The two black lines show the variation of best climb speed (v$_\text{y}$ - highest point of each curve) and best angle / steepest climb speed (v$_\text{x}$ - best ratio of climb speed over flight speed) with changing thrust. Note that the lowest line is for a glide. Since the green lines are limited by the stall speed, v$_\text{x}$ becomes constant over thrust at high enough thrust levels. The diagram has this oblong aspect ratio in order to make the graphic solution for the best angle speed possible.
If you interpret each power loading with the appropriate altitude, the lines also show the behavior of both speeds over altitude. In all cases the engine is run at maximum continuous power.
Now you want to climb at a constant climb rate. This means you will need to throttle back in order to limit climb speed and stay at the optimum speed at lower altitudes. This means that you will fly at the same power loading and need to adjust power with altitude to keep climb speed constant. This also means that you will stay at the same power loading and both optimum speeds should not change over altitude.

If one wishes to climb at (a rather modest) 500 feet per minute than one may not be constrained to fly an airspeed between Vx and Vy at all.
Why not try a cruise climb.
Rate of ascent will be dependent on throttle setting and pitch to the horizon.  A combination of these two will yield 500 fpm rate.
Rather than wallowing along at Vx at full throttle it may be better to fly at Vy, using the throttle to determine ascent rate.  Here's where it gets interesting, as lower engine RPM will be more efficient at lower airspeeds (with fixed pitch, to maintain optimal prop AoA to the relative wind).
But if you're only interested in 500 fpm up to 4500 feet, you wish to try an airspeed faster than Vy.  On this part of the drag curve, one can slow down to Vy as engine power decreases with altitude to maintain 500 fpm climb.


text:
Logging flight time as a ppl in IMC
I am a newly certificated private pilot. Am I able to log instrument flight time with another pilot in an airplane that I am not type rated for if we were to enter IMC conditions?

not type rated for

Assuming the aircraft requires a type rating, no. There are some circumstances that you can log time in an aircraft you are not rated for (solo, dual received, etc.), but none of them would apply to your circumstances, unless the other pilot is a CFII with the proper ratings providing you training.
If the aircraft does not require a type rating and you are rated in the category and class, then you can log PIC time and actual instrument time for the period where you are sole manipulator of the controls. The other pilot must be acting as PIC, but can only log any time they take the controls for.
It is probably not wise to do this. A CFII is trained to recover from their students trying their best to kill them. That is not part of the curriculum for an instrument rating.
If you choose to do this, you should annotate your log with a description of your circumstances. Seeing actual IMC that is not dual received will raise some eyebrows. The explanation that you chose to fly into IMC with an non-CFII pilot acting as PIC but chose not to hand over the controls to them may or may not cause those eyebrows to lower.

Thank you. I’m reading the regs and just building scenarios for myself and wanted better understanding. Thank you

@RTO Possibly, but one of OP's recent questions asks about receiving flight training in an Airbus, so it could go either way. I added a bit about the CFII having proper ratings, which should cover them being a CFI-A and also being rated in type and class.

If you enter IMC on a VFR flight plan, you're already in trouble.
If you file an IFR flight plan without an Instrument Rating, you're also in trouble.
If the other pilot is both Instrument Rated and Current, have them file and fly.  Any time he hands the controls over to you, you can gain experience, but you best NOT log it as IFR without an Instrument Rating.
If you choose to pursue your instrument rating, you will build the requisite hours by flying with your CFII, a Safety Pilot (no IMC!), or Solo (no instrument work while flying solo!).
It's all about learning the skills, not flying in IMC.
That said, a wise CFII will find time to give their students some actual time in IMC  for good, real-world practice.
Mine did, and it helped a good deal.


text:
How to calculate and understand glide distance?
How would I calculate my glide distance?
If I am at 8000 feet would I multiply 1.5 by 8 because the ratio is 1.5 NM per thousand ft?
Which would be 12 NM
Also where did a ratio of 9:5 come from?
I may have the numbers mixed up but I’m just trying to get an understanding on this topic because essentially I’m just trying to figure out how much distance in NM I would have if my engine cuts out at that altitude.

Your math is correct, but I don’t think your glide ratio is - that’s a horrible ratio for any training aircraft.  (Where did 9:5 come from?  How should we know, you typed it, where did you get it from?!) Anyway, what are you flying?  You will get some helpful and accurate answers if you provide a little more detail.  P.S. I’m editing your question because you are not asking how to calculate the ratio.

Not only where 9:5 comes from, but where 1.5 comes from. The space shuttle was 4.5:1 when landing, which is basically a brick.

1.5 nautical miles per 1000 feet is a glide ratio of 9.1:1, which is not far off from a typical trainer aircraft (a C152 is 9.7:1, for instance).

Chris- aha. I read it as 1500ft per 1000ft. Maybe that 9.1:1 shows they meant 9.5:1, not 9:5.

oops, I did the same thing!

I think pilots should keep in mind here that unless you're flying with test pilot precision, you may not get the "best case" numbers. It's smart to build in a fudge factor: maybe you will get closer to 1 nm / 1000' reliably when distracted with an engine restart and looking for a good spot.

@TypeIA Certainly you may lose some altitude from the startle factor. But you would have to fail the airspeed control pretty dramatically to lose 33% of your glide distance after that. Having too big a fudge factor is also a problem- it might convince you to ignore an airport or nice field that is in fact in easy glide distance in favor of a less suitable landing spot.

@Chris-RegenerateResponse I said "closer to." I mostly agree. Just wanted to point out that it's not a guarantee you'll get the range stated in the book. It just means a test pilot showed that range is possible. Variation in circumstances and skill has an influence that a responsible pilot shouldn't ignore.

To calculate your glide distance, you need to know the glide ratio at best glide of your aircraft. Here is an example from a Cessna 152:

Which shows that for every 1000 feet of altitude AGL a Cessna 152 should be able to glide 1.6 nautical miles. 1.6 nautical miles is 9722 feet, so this corresponds to a glide ratio of about 9.7 to 1. But since we usually think of altitudes in feet and ground distances in nautical miles, the figure 1.6 nautical miles per 1000 feet is probably more useful.
If your glide ratio is 1.5 nautical miles per 1000 feet, your math is correct. But that is just a common rule of thumb and may not be the correct ratio for your aircraft.
I don't know where you got 9:5. At a guess it is supposed to be 9:1 (which corresponds to around 1.5 nautical miles per 1000 feet).
Keep in mind that these are not calculations you will be relying on much in the cockpit. In a real engine-out situation there will be winds which will extend your glide (for a tailwind) or shorten it (for a headwind). The true best glide airspeed also depends on the wind speed- with a headwind you will want to be on a slightly faster airspeed and slightly slower for a tailwind.
In the cockpit, visual references will tell you how far you can glide- a spot that appears to be moving down in the windscreen is one that you will glide over at your current glide ratio, while one that is moving up in the windscreen is one that you will land short of. The spot you are gliding to is the spot that doesn't move.


text:
Can any aircraft beat this car's 0-400-0 km/h record of 28 seconds?
In 2024, the KOENIGSEGG Jesko Absolut set a new world record for 0-400-0 km/h. That's starting from 0 km/h, accelerating to 400 km/h and then decelerating to 0 km/h again.
Without such easy rolling friction and road friction to slow down, is there any type of aircraft that could beat this time?
EDIT:
For the purposes of this question, I don't want to use any extreme definition of aircraft.
I would limit the question to

manned aircraft
velocity in the horizontal plane without
gaining/losing more than 10% altitude by distance covered
without injury to the pilot/crew/passengers
ability to be reflown with
minimal maintenance/refuelling

A currently active question has some comments and answers saying that a missile is an aircraft.  The Sprint missile reaches 500 km/h in half a second, and (with a suitably placed target) returns to 0 km/h almost instantly, which is fine because it's not intended to be reflown.

What was the actual time of the record it set?

@CamilleGoudeseune, I'd upvote that as an answer...

@MichaelHall  A little under 28 seconds. Getting an aircraft up to that sort of speed quickly wouldn't be nearly as hard as slowing it back down again in comparable time.  Unless we use a set of rules that allows a missile for consideration, I doubt any aircraft will accomplish anything comparable -- by the time you're anywhere approaching 400 km/h, aircraft aren't intended to still be on the ground.

@Turkeyphant you need to put some boundaries in your question, otherwise "a missle" is a valid answer as said by Michael, but I'm not sure what you wanted to known. Are we talking about an aircraft on ground or on air? Are drones valid?

"Speed" is the rate of change of position in one dimension. Airplanes move, i.e., change their position in three dimensions. Saying "speed" in relation to an airplane is meaningless without specifying which direction you are measuring in. Also, "speed" is general measured relative to something else, for airplanes, speed can be measured relative to at least two different things: the ground or the air. Saying "speed" in relation to an airplane is meaningless without specifying what you are measuring against. You need to be more specific.

Just as an example: an airplane diving straight towards the ground has a ground speed of zero. When it pulls out of the dive and back into a zoom climb, it will very quickly go from a ground speed of zero to a very high ground speed and back to zero. I am almost certain that any modern jet fighter or even aerobatic propeller aircraft can do this in less than 28 seconds. But is that what you had in mind? Or, a different scenario: put an aircraft in a wind tunnel capable of producing wind speeds of 400 kph. Put a barrier in front of the aircraft. Move the barrier away. Put it back.

The aircraft will go from 0 airspeed to 400 kph and back without even running its engine. Oh, and it doesn't need to be an aircraft. A rock would do as well.

There is no way for a conventional aircraft to achieve that feat, because of purpose : transport people, things, or do specific tasks (military side), not race a track. Technically, a special aircraft with abnormally huge engines and very complex thrust reversers/spoilers could be a challenger. Would burn 40000lbs to accelerate then break like hell, not meant to fly. Means some company had to build that experimental useless thing for the sake of beating a car..... Not an aircraft anymore at that point. Just my humble opinion, ie, good luck finding such aircraft among existing purposeful ones.

I guess I would limit the question to manned aircraft, velocity in the horizontal plane without gaining/losing more than 5% altitude by distance covered and without injury to the pilot/crew/passengers and ability to be reflown with minimal maintenance/refuelling.

Yes.
Example:

The airspeed is in knots. 260 mph is 225 knots, but to adjust for wind over deck, I'll use 260 knots as the cutoff point.
The brake is released at 07:22, and by 07:33 the plane reaches 260 knots of airspeed. The second time, a fully loaded plane releases the brakes at 09:48 and reaches 260 kts at 10:03. For landing, at 03:58 the aircraft is at 260 knots approaching the deck, and at 04:52 it's stationary.
That comes down to 10 + 4 = 14 seconds for a lightly loaded naval fighter to reach 400 km/h and stop, and 20 seconds (15+5) while carrying an extra 10 tons. If you give it 28 seconds, it can reach 350 knots in 18 seconds (07:40) and stop in another 10. That's 400 mph or 650 km/h.
The F/A-18 can do it even quicker, but it relies on a catapult, which can be deemed unfair to the car; the Su-33 uses its own power only. For landing, since both car and aircraft brakes work against the ground, a trap is fair.
This is a flight sim, but it's highly accurate where energy performance is concerned. In real life, you'd simply need to do a rejected takeoff from a military runway equipped with a cable trap.
Only some aircraft can do this: it requires very good brakes, high thrust/weight, and an airframe that can take the forces from an arrestor hook. So, this is specific to naval fighters, which need to take off and land in less than 300 ft.

Fantastic, thanks

The answers to a currently active question confirm that a missile is an aircraft. The Sprint missile reaches 500 km/h in half a second, and (with a suitably placed target) returns to 0 km/h almost instantly, which is fine because it's not intended to be reflown.
For a reflyable aircraft to quickly decelerate from 400 km/h to zero, it would need a parachute like those used by dragsters or the Space Shuttle, but one heavy enough to brake in just a few seconds, much faster than commercial or military chutes.  Or missile-like retro-rockets.  (Edit: or a trap like an aircraft carrier's, as in Therac's answer.)  At any rate, something as exotic and nonmainstream as a Koenigsegg sports car, not something that you could sell hundreds of for any conceivable mission profile.

400km/h is about 111m/s so an aircraft in an unpowered vertical climb would come to a stop after a maximum of 11.32s.  With a budget of 28s total thats not a bad start; if the acceleration phase is horizontal then the rotation to vertical and then judicious use or airbrakes etc could shorten the time considerably.  Its also worth considering whether ‘zero’ is groundspeed or velocity; in the former case its a much easier proposition.

@Frog, yes, you've got an answer there!  If we interpret this as a test of raw propulsive force and braking force, then a fair comparison would be: stationary, then accelerate horizontally to 400 km/h, then climb/airbrake/cobra/whatever until stationary.  Climbing to bleed off speed is fair.  Zeroing your ground speed to claim you've "stopped" while still moving fast isn't:  then the car too could fall off a cliff, pull a chute, and claim that it had stopped while still drifting down.

As per my other comment,  I would limit the question to manned aircraft, velocity in the horizontal plane without gaining/losing more than 5% altitude by distance covered and without injury to the pilot/crew/passengers and ability to be reflown with minimal maintenance/refuelling. Do I need to edit the original question to clarify?

@Turkeyphant, yes, editing the question is how this usually goes.  Sometimes the edit is literally marked "Edit" boldface in its own paragraph, even though the edit history is visible.


text:
do planes go into a circle pattern to avoid law enforcement?
do planes depart airport (A) circle a few times then land at the same airport (A) to indicate to another plane inflight it is safe to land at (A) that airport by eluding from any possible law enforcement?

Going around the pattern and landing again is extremely common for a flight student (often with several touch-and-gos where they land but don't stop and immediately take off again).  This sounds a lot like somebody looking at a flight tracker and making things up.

That sounds improbable. There are various explanations for a plane taking off & flying as described, but the one offered sounds more like something out of a badly written movie script than anything realistic.
Airplanes have radios; transmitting something innocuous ("test 1,2,3,4,5,4,3,2,1") on an arranged frequency at an arranged time would be far easier and would attract far less attention.
What's described sounds extremely far-fetched.


text:
How do you find out if you need a permit for a crane near a local airport in Seymore Indiana?
We are constructing a new egg processing plant and will  a crane on site to erect the building.

Have you checked with the airport?

Not an answer since this is "link only" but the top Google result for "faa permit for crane" seems like it may meet your need: FAA site, FAQ

The relevant regulation is 14 CFR § 77.9. In relevant part, you need to inform the FAA and get permission if either is true:

The crane, or what you are constructing with it, will be taller than 200 feet above the ground level at the site.
The site is within 20000 feet of a runway, if the crane or the construction will pierce an imaginary 100 to 1 slope from the runway. So if it is 10000 feet away and more than 100 feet above the runway elevation, for example.

There are a few other rules as well, involving navigational aids and instrument approach procedures. Figuring this out is an very involved process. Fortunately the FAA has a tool where you can enter the latitude and longitude of your site and it will figure it out for you.
If you are required to notify the FAA, you must do it 45 days before you plan to erect the crane, and wait for the FAA to inform you that it has been determined to be no hazard to air navigation.
In the case of KSER, the map looks something like this.
The grey areas (about 4 miles in radius) are the areas around the runways that I mentioned above, and the rectangular areas are extra protection for approaches to the runways.

Very interesting. It's about half the IFR obstacle clearance slope of 200ft/nm in an inverted cone centered in each runway threshold.